1. Field of the Invention
The present invention relates generally to dispersion of load among a plurality of wireless LAN (Local Area Network) access points to which a plurality of clients (such as terminal devices) are connected, and more particularly, to a wireless communication apparatus, a load dispersing method thereof, a load dispersing program thereof, and a wireless communication system, which are prevented from uneven distribution of load among the wireless LAN access points, for example, uneven distribution of the number of clients.
2. Description of the Related Art
In a wireless LAN system having a plurality of access points, a plurality of clients are connected by wireless to each access point. If connection of a client to each access point is left to the freedom of the two parties, uneven distribution will occur in the number of clients connected to respective access points.
With respect to prevention of such uneven distribution of load among access points, Japanese Patent Application Laid-Open Publication No. 2004-221684 discloses that, based on a connection request from a terminal device, a verifying device determines loading condition of access points and, based on such determination, instructs the client to try to connect with other access point rather than the access point the connection to which is requested as a method of dispersing the load among the access points. Japanese Patent Application Laid-Open Publication No. 1999-126185 discloses that in response to the connection request from a client, the client is assigned to a communication process which has the least number of connections. Japanese Patent Application Laid-Open Publication No. 2006-101540 discloses that upon receipt of a probe signal from a terminal device, judgment is made of the loading condition of base station devices and, based on the judgment, a base station device is selected.
Incidentally, the dispersion of load among access points without involvement of information exchange among access points may simply be realized by so arranging that the number of clients that can be connected to each access point is limited and that when such limited number is exceeded for an access point, clients will flow to other access points. Specifically, the number of client connections that each access point accommodates is registered and any connection request in excess of such number of client connections is not accepted, namely, each access point may be equipped with a function of rejecting, ignoring, etc. In this case, since it is expected that with respect to the client whose connection request was rejected by an access point, other access point will accept the connection request, dispersion of load can simply be achieved. Namely, simple load dispersion can be achieved because of no need for such monitor of the number of connections or such judgment of loading condition as disclosed in Japanese Patent Application Laid-Open Publication No. 2004-221684, Japanese Patent Application Laid-Open Publication No. 1999-126185, or Japanese Patent Application Laid-Open Publication No. 2006-101540.
However, when an upper limit is set to the number of connections for the access points AP#1 and AP#2, as shown in FIG. 13, the number of connections of clients CL satisfies the upper-limit number of connections “10” at the specific access point AP#1, while it is inevitable that no connection is made or an extremely low number of connections are made with the other access point AP#2, and still the uneven distribution of load among the access points can not be prevented.
With respect to the problem that the optimization of load can not be achieved even if the upper limit is set to the number of connections for the access points as seen above, Japanese Patent Application Laid-Open Publication No. 2004-221684, Japanese Patent Application Laid-Open Publication No. 1999-126185, and Japanese Patent Application Laid-Open Publication No. 2006-101540 do not contain the disclosure or suggestion thereof or the disclosure or suggestion of the solution thereof. A problem of complication of a communication system is caused by the introduction of a management system equipped with a device for monitoring the number of connections or judging the loading condition as described in Japanese Patent Application Laid-Open Publication No. 2004-221684, Japanese Patent Application Laid-Open Publication No. 1999-126185, and Japanese Patent Application Laid-Open Publication No. 2006-101540.